Enzymatic Synthesis of Glucosyl Rebaudioside A and its Characterization as a Sweetener.

Rebaudioside A was modified via glucosylation by recombinant dextransucrase of Leuconostoc lactis EG001 in Escherichia coli BL21 (DE3), forming single O-α-D-glucosyl-(1″→6') rebaudioside A with yield of 86%. O-α-D-glucosyl-(1″→6') rebaudioside A was purified using HPLC and Diaion HP-20 and its properties were characterized for possible use as a food ingredient. Almost 98% of O-α-D-glucosyl-(1″→6') rebaudioside A was dissolved after 15 days of storage at room temperature, compared to only 11% for rebaudioside A.

Bacteroides koreensis sp. nov. and Bacteroides kribbi sp. nov., two new members of the genus Bacteroides.

Three bacterial isolates from human faeces, YS-aM39, R2F3-3-3 and R2F3-5-1, were characterized as Gram-negative, strictly anaerobic, non-spore-forming, non-motile, and rod-shaped. Isolate YS-aM39 formed a distinct line of descent, showing greatest 16S rRNA gene sequence relatedness with R2F3-3-3 (97.5 %), R2F3-5-1 (97.

Improvement of the pharmacological activity of menthol via enzymatic β-anomer-selective glycosylation.

Menthol has a considerable cooling effect, but the use range of menthol is limited because of its extremely low solubility in water and inherent flavor. (-)-Menthol β-glucoside was determined to be more soluble in water (>27 times) than (-)-menthol α-glucoside; hence, β-anomer-selective glucosylation of menthol is necessary. The in vitro glycosylation of (-)-menthol by uridine diphosphate glycosyltransferase (BLC) from Bacillus licheniformis generated (-)-menthol β-glucoside and new (-)-menthol β-galactoside and (-)-menthol N-acetylglucosamine.

Description of Absiella argi gen. nov., sp. nov., and transfer of Eubacterium dolichum and Eubacterium tortuosum to the genus Absiella as Absiella dolichum comb. nov. and Absiella tortuosum comb. nov.

Gram-positive, straight or slightly curved rod-shaped bacteria, designated as strains N6H1-5 and N6H1-3, were isolated from fecal samples of old dog. The analysis of 16S rRNA gene sequences indicated that the isolates belonged to the Clostridium cluster XVI and were closely related to Eubacterium dolichum KCTC 5832, Eubacterium tortuosum DSM 3987, Clostridium innocuum KCTC 5183, Allobaculum stecoricanis DSM 13633, Eubacterium limosum KCTC 3266, and Clostridium butyricum KCTC 1871, with 94.0%, 93.

Structural insight for substrate tolerance to 2-deoxyribose-5-phosphate aldolase from the pathogen Streptococcus suis.

2-deoxyribose-5-phosphate aldolase (DERA) is a class I aldolase that catalyzes aldol condensation of two aldehydes in the active site, which is particularly germane in drug manufacture. Structural and biochemical studies have shown that the active site of DERA is typically loosely packed and displays broader substrate specificity despite sharing conserved folding architecture with other aldolases. The most distinctive structural feature of DERA compared to other aldolases is short and flexible C-terminal region.

Glucosyl Rubusosides by Dextransucrases Improve the Quality of Taste and Sweetness.

Glucosyl rubusosides were synthesized by two dextransucrases. LcDexT was obtained from Leuconosotoc citreum, that LlDexT was obtained from Leuconostoc lactis. LcDexT and LlDexT regioselectively transferred a glucosyl residue to the 13-O-glucosyl moiety of rubusoside with high yield of 59-66% as analyzed by TLC and HPLC.

Silver wire amplifies the signaling mechanism for IL-1beta production more than silver submicroparticles in human monocytic THP-1 cells.

Silver materials have been widely used in diverse fields. However, their toxicity and their mechanism, especially in different forms, have not been studied sufficiently. Thus, cytotoxicity, apoptosis, and interleukin-1beta (IL-1β) production were investigated using macrophage-like THP-1 cells in the presence of Ag microparticles (AgMPs, 2.

Enzymatic Biosynthesis of Novel Resveratrol Glucoside and Glycoside Derivatives.

A UDP glucosyltransferase from Bacillus licheniformis was overexpressed, purified, and incubated with nucleotide diphosphate (NDP) d- and l-sugars to produce glucose, galactose, 2-deoxyglucose, viosamine, rhamnose, and fucose sugar-conjugated resveratrol glycosides. Significantly higher (90%) bioconversion of resveratrol was achieved with α-d-glucose as the sugar donor to produce four different glucosides of resveratrol: resveratrol 3-O-β-d-glucoside, resveratrol 4'-O-β-d-glucoside, resveratrol 3,5-O-β-d-diglucoside, and resveratrol 3,5,4'-O-β-d-triglucoside. The conversion rates and numbers of products formed were found to vary with the other NDP sugar donors.

Peptoniphilus rhinitidis sp. nov., isolated from specimens of chronic rhinosinusitis.

Chronic rhinosinusitis (CRS) is an inflammatory disorder of the nasal cavity and paranasal sinus related to bacterial infection. A previous study suggested that a specific bacterial group may have an important role in the course of CRS. In this study, bacteria isolated from CRS patients were characterized.

First thermostable endo-β-1,4-glucanase from newly isolated Xanthomonas sp. EC102.

A novel gene encoding thermostable endoglucanase was identified in Xanthomonas sp. EC102 from soil. The gene had 1,458 base pairs of open reading frame, which encode a 52-kDa protein of 486 amino acid residues.

Genome-wide analysis of redox reactions reveals metabolic engineering targets for D-lactate overproduction in Escherichia coli.

Most current metabolic engineering applications rely on the inactivation of unwanted reactions and the amplification of product-oriented reactions. All of the biochemical reactions involved with cellular metabolism are tightly coordinated with the electron flow, which depends on the cellular energy status. Thus, the cellular metabolic flux can be controlled either by modulation of the electron flow or the regulation of redox reactions.

Enzymatic synthesis of novel phloretin glucosides.

A UDP-glycosyltransferase from Bacillus licheniformis was exploited for the glycosylation of phloretin. The in vitro glycosylation reaction confirmed the production of five phloretin glucosides, including three novel glucosides. Consequently, we demonstrated the application of the same glycosyltransferase for the efficient whole-cell biocatalysis of phloretin in engineered Escherichia coli.

Enzymatic glycosylation of nonbenzoquinone geldanamycin analogs via Bacillus UDP-glycosyltransferase.

Geldanamycin (GM) is a naturally occurring anticancer agent isolated from several strains of Streptomyces hygroscopicus. However, its potential clinical utility is compromised by its severe toxicity and poor water solubility. For this reason, considerable efforts are under way to make new derivatives that have both good clinical efficacy and high water solubility.

Enzymatic synthesis of puerarin glucosides using Leuconostoc dextransucrase.

Puerarin (P), an isoflavone derived from kudzu roots, has strong biological activities, but its bioavailability is often limited by its low water solubility. To increase its solubility, P was glucosylated by three dextransucrases from Leuconostoc or Streptococcus species. Leuconostoc lactis EG001 dextransucrase exhibited the highest productivity of puerarin glucosides (P-Gs) among the three tested enzymes, and it primarily produced two P-Gs with a 53% yield.

Mass production of rubusoside using a novel stevioside-specific β-glucosidase from Aspergillus aculeatus.

Rubusoside (R) is a natural sweetener and a solubilizing agent with antiangiogenic and antiallergic properties. However, currently, its production is quite expensive, and therefore, we have investigated nine commercially available glycosidases to optimize an economically viable R-production method. A stevioside (ST)-specific β-glucosidase (SSGase) was selected and purified 7-fold from Aspergillus aculeatus Viscozyme L by a two-step column chromatography procedure.

Bacillus manliponensis sp. nov., a new member of the Bacillus cereus group isolated from foreshore tidal flat sediment.

A Gram-positive, endospore-forming, new Bacillus species, strain BL4-6(T), was isolated from tidal flat sediment of the Yellow Sea. Strain BL4-6(T) is a straight rod, with motility by peritrichate flagella. The cell wall contains meso-diaminopimelic acid, and the major respiratory quinone is menaquinone-7.

Description of Lysinibacillus sinduriensis sp. nov., and transfer of Bacillus massiliensis and Bacillus odysseyi to the genus Lysinibacillus as Lysinibacillus massiliensis comb. nov. and Lysinibacillus odysseyi comb. nov. with emended description of the genus Lysinibacillus.

A Gram-positive, rod-shaped, endospore-forming bacterium, designated strain BLB-1(T), was isolated from samples of tidal flat sediment from the Yellow Sea. 16S rRNA gene sequence analysis demonstrated that the isolate belonged to the Bacillus rRNA group 2 and was closely related to Bacillus massiliensis CIP 108446(T) (97.4%), Bacillus odysseyi ATCC PTA-4993(T) (96.

Expression and characterization of a novel deoxyribose 5-phosphate aldolase from Paenibacillus sp. EA001.

A novel deoC gene was identified from Paenibacillus sp. EA001 isolated from soil. The gene had an open reading frame (ORF) of 663 base pairs encoding 220 amino acids with a molecular mass of 24.

NF-kappaB/STAT3/PI3K signaling crosstalk in iMyc E mu B lymphoma.

Background: Myc is a well known driver of lymphomagenesis, and Myc-activating chromosomal translocation is the recognized hallmark of Burkitt lymphoma, an aggressive form of non-Hodgkin's lymphoma. We developed a model that mimics this translocation event by inserting a mouse Myc cDNA gene into the immunoglobulin heavy chain locus, just upstream of the intronic Emu enhancer. These mice, designated iMyc E mu, readily develop B-cell lymphoma.

Purification and characterization of a novel glucansucrase from Leuconostoc lactis EG001.

A gene encoding glucansucrase was identified in Leuconostoc lactis EG001 isolated from lactic acid bacteria (LAB) in Kimchi, a traditional Korean fermented food. The L. lactis EG001 glucansucrase gene consists of 4503 bp open reading frame (ORF) and encodes an enzyme of 1500 amino acids with an apparent molecular mass of 165 kDa.

Activity assay for nisin-like acidic bacteriocins using an optimal pH-conditioned gel matrix.

A new zymography for detecting nisin-like acidic bacteriocins was developed using a tricine-sodium dodecyl sulfate (SDS) gel and an acidic gel matrix (pH 4.0). After electrophoresis, proteins in the tricine gel were electrotransferred to an optimal pH-conditioned gel matrix (OP-CGM).

Bacillus acidiproducens sp. nov., vineyard soil isolates that produce lactic acid.

Two novel spore-forming lactic acid bacteria, strains SL213T and SL1213, were isolated from vineyard soils in Korea. Cells of both isolates were rod-shaped bacilli and contained subterminal, ellipsoidal spores. Strains were facultatively anaerobic, catalase-positive, oxidase-negative and motile with single flagella.

Mixed-substrate (glycerol tributyrate and fibrin) zymography for simultaneous detection of lipolytic and proteolytic enzymes on a single gel.

A new zymography method for simultaneous detection of two different enzymatic activities (lipolytic and proteolytic) using a single SDS-containing or native-conformation gel and a mixed-substrate (glycerol tributyrate and fibrin) (MS)(1) gel was developed. After routine electrophoresis, SDS in the gel was removed by treatment with Triton X-100. Gel proteins were electrotransferred to the MS gel.

Cloning, expression, and characterization of a new deoxyribose 5-phosphate aldolase from Yersinia sp. EA015.

A new deoC gene encoding deoxyribose 5-phosphate aldolase (DERA) was identified in Yersinia sp. EA015 isolated from soil. The DERA gene had an open reading frame (ORF) of 672 base pairs encoding 223 amino acids to yield a protein of molecular mass 24.